Albert F. Yee

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Cells are known to be surrounded by nanoscale topography in their natural extracellular environment. The cell behavior, including morphology, proliferation, and motility of bovine pulmonary artery smooth muscle cells (SMC) were studied on poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) surfaces comprising nanopatterned gratings with 350(More)
A typical epoxy formulation can absorb several weight percent of water, seriously degrading the physical properties of the resin. In two preceding publications (Soles, C. L.; Chang, F. T.; Bolan, B. A.; Hristov, H. A.; Gidley, D. W.; Yee, A. F. J Polym Sci Part B: Polym Phys 1998, 36, 3035; Soles, C. L.; Chang, F. T.; Gidley, D. W.; Yee, A. F. J Polym Sci(More)
A reversal imprinting technique was developed in this study. A polymer layer was first spin coated on a patterned hard mold, and then transferred to a substrate under an elevated temperature and pressure. The reversal imprinting method offers an advantage over conventional nanoimprinting by allowing imprinting onto substrates that cannot be easily spin(More)
A new class of epoxy nanocomposites with completely defined organic/inorganic phases was prepared by reacting octakis(glycidyldimethylsiloxy)octasilsesquioxane [(glydicylMe(2)SiOSiO(1.5))(8)] (OG) with diaminodiphenylmethane (DDM) at various compositional ratios. The effects of reaction curing conditions on nanostructural organization and mechanical(More)
Lifetime analysis of positronium annihilating in nanometer voids is used to study the thermal expansion behavior of thin, Si-supported polystyrene films near the glass transition temperature Tg. A reduction in void volume expansion is correlated with a reduction in the apparent Tg as film thickness decreases. Our results can be fitted using a three-layer(More)
This article describes results on using steered molecular dynamics (SMD) simulations and experimental single molecule force spectroscopy (SMFS) to investigate the relationship between hydrogen bonding and mechanical stability of a series of homodimeric β-sheet mimics. The dimers consisting of 4, 6, and 8 H-bonding sites were modeled in explicit chloroform(More)
Positron annihilation spectroscopy is used to characterize the ortho-positronium lifetime, tau(3), in a broad range of small molecule organic glasses over a wide temperature range. The magnitude and thermal variations of tau(3) reflect changes in the dielectric alpha-relaxation time tau(alpha) and its non-Arrhenius or "fragile" characteristics. tau(3) also(More)
Bacteria that adhere to the surfaces of implanted medical devices can cause catastrophic infection. Since chemical modifications of materials' surfaces have poor long-term performance in preventing bacterial buildup, approaches using bactericidal physical surface topography have been investigated. The authors used Nanoimprint Lithography was used to(More)
An existing model that relates the annihilation lifetime of positronium trapped in subnanometer pores to the average size of the pores is extended to account for positronium in any size pore and at any temperature. This extension enables the use of positronium annihilation lifetime spectroscopy in characterizing nanoporous and mesoporous materials, in(More)
The effect of physical aging on the dissolution and mechanical properties of hydroxypropyl methyl-cellulose phthalate (HPMCP) was investigated. Dissolution rate measurements were performed on films which, initially above the glass transition temperature, T g, were quenched to a sub-T g storage temperature, aged at that temperature for a period of time and(More)